XML 140 R123.htm IDEA: XBRL DOCUMENT v3.8.0.1

Regulatory Assets and Liabilities (Emera Maine ) (Details) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017 CAD ($) km	Dec. 31, 2016 USD ($)	Dec. 31, 2016 CAD ($)
Public Utilities, General Disclosures [Line Items]
Regulatory Assets		$ 1,376		$ 1,322
Emera Maine [Member] | Maine Public Utilities Commission (MPUC) [Member] | Electric Distribution [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Approved Return on Equity, Percentage			9.00%
Public Utilities, Approved Equity Capital Structure, Percentage			49.00%
Public Utilities, Approved Rate Increase (Decrease), Percentage			3.75%
Public Utilities, Approved Rate Increase (Decrease), Amount			$ 4
Bangor Hydro District [Member] | Federal Energy Regulatory Commission (FERC) [Member] | Electric Transmission [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Approved Return on Equity, Percentage		10.57%	10.57%
Bangor Hydro District [Member] | Minimum [Member] | Federal Energy Regulatory Commission (FERC) [Member] | ISO-New England (ISO-NE) [Member] | Electric Transmission [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Approved Return on Equity, Percentage		11.07%	11.07%
Bangor Hydro District [Member] | Maximum [Member] | Federal Energy Regulatory Commission (FERC) [Member] | ISO-New England (ISO-NE) [Member] | Electric Transmission [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Approved Return on Equity, Percentage		11.74%	11.74%
Maine Public Service District [Member] | Federal Energy Regulatory Commission (FERC) [Member] | Electric Transmission [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Approved Return on Equity, Percentage		9.60%	10.20%
Barbados Light & Power Company Limited [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Approved Return on Equity, Percentage		10.00%	10.00%
Dominica Electricity Services Ltd. [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Approved Return on Equity, Percentage		15.00%	15.00%
Grand Bahama Power Company Limited [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Approved Return on Equity, Percentage	8.50%	8.80%	8.80%
Brunswick Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Length Of Pipeline | km		145

X

- References

No definition available.

+ Details

Name:	ema_LengthOfPipeline
Namespace Prefix:	ema_
Data Type:	num:lengthItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Percentage of public utility's approved equity to capital, including debt and equity.

+ References

No definition available.

+ Details

Name:	us-gaap_PublicUtilitiesApprovedEquityCapitalStructurePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount of public utility's approved rate increase (decrease) by regulatory agency.

+ References

No definition available.

+ Details

Name:	us-gaap_PublicUtilitiesApprovedRateIncreaseDecreaseAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Percentage of public utility's approved rate increase (decrease) by regulatory agency.

+ References

No definition available.

+ Details

Name:	us-gaap_PublicUtilitiesApprovedRateIncreaseDecreasePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Percentage of public utility's approved return on equity.

+ References

No definition available.

+ Details

Name:	us-gaap_PublicUtilitiesApprovedReturnOnEquityPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_PublicUtilitiesGeneralDisclosuresLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The amount for the individual regulatory asset as itemized in a table of regulatory assets as of the end of the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 340
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382

+ Details

Name:	us-gaap_RegulatoryAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

Name:	dei_LegalEntityAxis=ema_EmeraMaineMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_RegulatoryAgencyAxis=ema_MainePublicUtilitiesCommissionMpucMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PublicUtilityAxis=us-gaap_ElectricDistributionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=ema_BangorHydroDistrictMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_RegulatoryAgencyAxis=ema_FederalEnergyRegulatoryCommissionFercMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PublicUtilityAxis=us-gaap_ElectricTransmissionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PublicUtilitiesRegulatoryProceedingAxis=ema_IsoNewEnglandIsoNeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=ema_MainePublicServiceDistrictMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=ema_BarbadosLightPowerCompanyLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=ema_DominicaElectricityServicesLtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=ema_GrandBahamaPowerCompanyLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=ema_BrunswickPipelineMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: